A holster assembly includes an adaptor flange securable to a firearm and formed with an opening, a garment mounting provision, and a holster clip including resilient arms that include inner faces. One of the resilient arms includes a mounting feature that couples to the garment mounting provision. When the firearm is slid and fully holstered into the holster clip, the inner faces of the resilient arms click over a border of the opening and the firearm is securely held in the holster assembly.